Safety critical system

A method in a computerized nuclear power station monitoring system, comprising:

• storing a database comprising a task category database comprising a plurality of task category information elements comprising a safety function information element and a reactor protection information element, each task category information element being associated with at least one technical functional requirement and at least one technical design principle, each technical design principle being comprised in a technical design principle list, the technical design principle list comprising redundancy, diversity, separation and isolation, each functional requirement being comprised in a functional requirement list, the functional requirement list comprising reactivity control, core cooling and safe shut-down, and an equipment database configured to store at least one equipment information element;
• determining, responsive to receipt in the computerized monitoring system of a failure notification concerning a first equipment information element, using the database, a set comprising each technical design principle associated with each task category information element associated, via database relations, with the first equipment information element, and
• identifying, based on each technical design principle comprised in the set, a technical constraint of an action compensating, at least partly, effects of the failure identifier in the failure notification.

A method, comprising:

• defining a task category information element, the task category information element being associated with at least one functional requirement and at least one design principle;
• associating the task category information element with at least one architecture definition information element;
• associating each of the at least one architecture definition information element with at least one system-level information element, and
• verifying the system described by the at least one architecture definition information element and associated system-level information elements is compliant with the at least one design principle.

A database system, comprising:

• a task category database configured to store at least one task category information element, each task category information element being associated with at least one functional requirement and at least one design principle;
• an architecture database configured to store at least one architecture definition information element;
• a system database configured to store at least one system-level information element,
• wherein each of the at least one task category information element is associated with at least one architecture definition information element and each of the at least one architecture definition information element is associated with at least one system-level information element.